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Radiator fan


Well-Known Member
Today, I hung out with some members from the HAMB and chowed down on some great gumbo. A great bunch of guys and a great source of info for hot rods. Well, one of the members is running a SBC with a flex fan and no shroud. I didn't get his engine specs, but he says he doesn't overheat with it. I'm thinking I may be able to do the same. My engine is a stock 305 and my radiator is rated for 650HP. Running a flex fan would sure make for a clean setup and maybe save a few bucks over an electric fan setup. I'd still probably run a shroud though. If anything, just to keep stuff from going into the fan. Like fingers.:eek:


Is anyone running a similar application with no problems?
No one?:confused:
My Son and I were just having this conversation tonight while he was working on his '29. He wants it to be traditional pretty much, but he also realizes he has a 455 Olds there that needs a lot of cooling, and we live in Florida. :eek:

He asked me how mechanical fans were, and I told him I switched over to electric years ago and will probably not go back. Electrics work better at low speeds, like traffic lights, and are much safer. I've seen mechanical fans explode and open up a gash in the hood like a can opener. I have also cut my fingers more than once while tuning the car when the blades hit my hand.

Mechanical fans can work great if you get them inside a shroud and close to the radiator. Lots of people use them, but for the reasons I mentioned above I really won't go back.

I did some work on my T tonight getting ready for the trip to Billetproof, and I let it sit there and idle until the temp came up to 180. Then I turned the electric fan on and it dropped it to 150 in about 1 minute. That is why I like them so much.

Fred I have an aluminum flex fan on the tub. It has a 383 stroker in it. I took a 16" electric fan off and used the flex fan instead. No shroud either. It keeps it plenty cool.
I am running a fixed 6 blade fan. I originally had a Flex fan but did not particularly care for the look of it. (Purely a matter of personal preference.) When I was building, I allowed plenty of room to use an electric fan if the mechanical fan was not up to the task. I just do not like the look or the sound of an electric fan. (There again, personal preference.) However, my mechanical has proven to be more than capable of the task of keeping my engine cool even in the HOT Florida summer which is when I enjoy driving it the most.
Thanks guys. I know electric fans work VERY well, but I too am looking for a traditional look. Now I have another option to play with. I'll let you all know what I decide to go with.

Thanks again for responding.
Here ya go Fred. A 10" flex fan, no shroud. The only time its ever over-heated was during a smog check in 115 degree heat. I will probably add a fan this Summer anyway.

I run an electric on my 350 sbc bucket. Its a GM something, the stock shroud was just the perfect size to fit a 65 mustang radiator. It has never overheated.
I ran a stock fan on my 55 chev with a moderately warmed up 350, no shroud and stock 55 radiator with the same results. I have got them warm (up in the 230 degree range) but ya gotta run the snot out of them..My first finger in fan incident was pulling the vacuum advance line off the distributor of a 351C ford, instant fingers in fan moment. Only did that once.
Never been a big "fan" (pun intended) of the old manual fan just for the noise. Would you have room for a clutch type?
Yogi said:
Never been a big "fan" (pun intended) of the old manual fan just for the noise. Would you have room for a clutch type?

Yogi, I still have not even measured the space between my pulley and the radiator. I'm still getting info, but I'm leaning toward a regular fan. Mainly for the look. Now, if I can't figure out a way to make a shroud look good, I'll go with the electric fan.
Thermostatic clutch fan with a shroud is the absolute best way to go. Just not very stylish. I also don't like electrics as the sound just isn't right, especially on an older style hot rod.

A flex fan will probably work just fine on anything under 300hp. Just watch those fingers (!) and don't over-rev it. Most are not rated for more than 5000 engine rpm or so using stock pulleys. I've seen blades go clean through a hood!
12 volt fans canbe called traditional ,in that they started being used a lot by late 60's,but that kind of depens on what time frame your calling traditional ?
I remember that in the 50's and 60's just using what ever I could get [mostly free] that both worked and looked good too!
I'm Running electric.....because.

I'm using the 16" Perma-Cool Electric because the centerline of the fan on the Caddy was way too high to center on the radiator.
I have the Mustang 3 row radiator Modine #2301, it seems to cool Ok in the shop, but thats not out on the Highway or in heavy traffic, we'll see, others are using this radiator even with BB Chebby's and without trouble. The Caddy has pretty big water jackets...
I plan to hook up a temp. switch on the fan control.
You are correct, those Flex Fans and the Electric (mine has a alum. fan.) do make lots of noise......"BH"

Mine had a brand X electric on the car when I bought it. The fan was attached with the ny-lok ties and summarily broke whrn I took my oldest daughter out for a test drive and then it fell all the way off sans one tie when I took the wife out. I replaced them and my buddy and I got them too tight and the blade was grazing the core. Hayden tech.'s could not tell me how to remove the ny-lok ties without screwing the core up. :confused:

The dude said they go on one way. :eek: I said yeah, I know, how do you get 'em off. He says. I don;t know. Long story short. a cheap soldering iron works great.

Needless to say I ended up buying a new fan and mount kit from T.P. and after making a call for clarification before mounting I am very happy.

There just isn't room for a bolt on fan without raising the radiator and fouling the look. The electric fan is straight wired currently but I am going to use the thermostat and wiring kit provided for automatic function.

Just my $.02.
Yogi said:
Never been a big "fan" (pun intended) of the old manual fan just for the noise. Would you have room for a clutch type?

I'll second that. Flex fans make the car sound like an airplane. The other thing I dont like about them is the power draw, removing the fan will noticably improve throttle response.

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